Effect of Storage Temperature on Fruit Hardness and Anthocyanin Biosynthesis in Red Peeled Banana (Musa acuminata Hongmeiren)

Abstract

Bananas (Musa spp.) are a popular tropical fruit grown worldwide and are typically harvested when 70% to 80% plump. Postharvest storage is crucial for maintaining fruit quality, with temperature playing a key role due to banana sensitivity to low temperatures. Red peeled bananas, such as the cultivar Hongmeiren, stand out for their unique red peel and pink pulp when ripe. These bananas offer nutritional benefits and are rich in anthocyanins compared with yellow bananas. This study focused on the hardness change, anthocyanin content, and the expression of related genes in red peeled bananas at different temperatures. Results showed that pulp hardness reached an edible state after 4 days at 19 and 25 °C, with stability thereafter. Storage time at 10 °C was longer and anthocyanin content remained stable across temperatures. Gene expression analysis indicated that genes including MaPAL, MaCHS, MaCHI, MaDFR, and MaANS related to anthocyanin synthesis were highly expressed at 10 °C, potentially preserving anthocyanin content and fruit appearance. Although higher anthocyanin content was observed at 19 and 25 °C, black spots appeared on the fruit peel after 8 days, affecting its quality. After 30 days of storage at 10 °C, a significant number of black spots appeared on the peel of the fruit, leading to a gradual loss of its nutritional value. This study indicates that red peeled bananas can be stored for longer periods while maintaining their appearance quality at 10 °C, as opposed to 19 and 25 °C. Hence, it is recommended to store red peeled bananas at low temperatures, especially following ethylene treatment or during periods of high temperatures.